Tag Archives: Performance

Autoboxing Performance

Preface Because of my previous post about autoboxing I get many search queries about autoboxing performance. Now I’m curious, too. So let’s get ready for some benchmarks. When we talk about boxing performance, then we always have two sides. Throughput … Continue reading

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The size does matter! (partly)

Have you ever asked yourself, what memory size does an object or a primitive data type really uses? In general it uses a multiple of WORD. http://en.wikipedia.org/wiki/Word_%28computing%29 That means a multiple of 4 byte (32bit) or 8 byte (64bit), if … Continue reading

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Autoboxing: Traps and Advantages

What is ‘autoboxing’ some people might ask? Autoboxing is a feature, which was added in Java 5. Autoboxing is the automatic conversion of primitive data types like int, double, long, boolean to its wrapper Object Integer, Double… and vice versa. … Continue reading

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The costs of String concatenation (+) or what String appending really does

String concatenation (e.g. “fu” + “bar”) are for most developers a mystery what it really does. The simple case Something like will usually be appended at compile time. So if you decompile this you see: The final case What happens … Continue reading

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Java Performance Tuning with maximizing Integer.valueOf(int)

With http://java.sun.com/javase/6/docs/api/java/lang/Integer.html#valueOf%28int%29 or auto boxing(uses internal a valueOf too) the cached Integer values will be used if they are between -127 and +128. Now I found coincidentally(by looking at the source) on a Java feature or more exactly on a … Continue reading

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